Crankcase for internal combustion engines



Feb. l, 1938. K. wlLcKEN 2,106,939

CRANKCASE FOR INTERNAL COMBUSTION ENGINES Filed April 2, 1936 PatentedFeb. 1, 1938 UNITED STATES PATENT OFFICE Karl Wlcken, Dessau-Ziebigk,Germany, as-

signor to Junkers Flugzeugund Motorenwerke Aktiengesellschaft, Dessau,Germany Application April 2, 1936, Serial No. 72,256 In Germany April10, 1935 3 Claims.

My invention relates to crankcases for internal combustion engines, andmore particularly to Aan improved crankcase for engines, in which thecylinders or series of cylinders are arranged on opposite sides of thecrankshaft.

Internal combustion engines of the type aforesaid are preferably used invehicles and in view thereof the crankcases of such engines must conformto numerous requirements.

In order to meet these requirements the crankcase must be formed as arigid girder, which is not deformed to any noticeable degree`by theforces acting on it, thus preventing the obnoxious jamming of thecrankshaft in its bearings, which are rig-idly connected with thecrankcase. Apart from the requirements as to strength to which thecrankcaseis subject, requirements of operation must also be consideredand in particular provisions must be made for adapting thecrankcasestructure for a ready insertion and removal of the crankshaft.

It is an object of the present invention to combine the cylinders orseriesof cylinders in an engine of this type into a self-contained unit.

It is a further object of my invention to provide a crankcase, whichpermits of an easy insertion and removal of the crankshaft, e. g., forrepair purposes.

According to the present invention the crank- 0 case is formed as anintegral casting of U-shaped cross section, in which the legs extendparallel to the plane passing through the cylinder axes. One of theopposed cylinders or cylinder series is attached to the bottom of the u-shaped case,

5 while the other cylinder or series of cylinders is or are mounted onthe free ends of the U-legs in a manner such that these legs are bracedrela- 1 tive to each other. The crank bearings arranged on the inside ofthe case bottom are each prol vided with a bearing cap separately.inserted in the U-cavity, and present a joint, which extends at rightangles to the mean plane of the cylinders.

A crankcase of this kind involves great advantages in engines of theopposed cylinder type.

I n cooperation with the cylinders, it provides the required rigidity inthe various dimensions, and in. spite of its integral structure renderspossible an easy insertion and removal of the crankshaft, after thecylinder or cylinder series arranged on the open side of the U-structirehave been re` moved.

In the drawing aiii'xed to this specication and i forming part thereoftwo embodiments lof this invention are shown diagrammatically by way ofexample.

In the drawing Fig. 1 is a section at right angles to the crankshaft andin the plane of the cylinder axes of two 5 opposed cylinders,

Fig. 2 is -another section at right angles to the crankshaft taken,through the space between two adjacent cylinders, e. g., on the lineII-II of Fig. 3, and

Fig. 3 is `a section longitndinal with respect to the crankshaft and atright angles'to the cylinder axes, e. g., on the line III--IlI in Fig.1, of one embodiment of the invention.

Fig. 4 is a section, similar to that shown in 15 Fig. 2, of anotherembodiment.

Referring to the drawing and first to Figs. 1, 2 and 3, I and .2 are theopposed cylinders or cylinder series of an internal combustion engine.The opposed cylinders are connected with each other by an integralcrankcase 'of U-shape, the U being formed by the bottom portion 4 andthe two legs 4a and 4b. These legs extend parallel to the plane passingthrough the cylinder axes.

The cylinder or cylinder series I is mounted by means of the iiange 5 onthe free ends of the legs 4a and 4b of the crankcase, forming a bracefor these two legs. The cylinder or cylinder series 2 is mounted bymeans of the flange 6 on thek bottom portion 4 of the U-shaped case..The 30 cylinders or cylinder series l and 2 are attached to thecrankcase 4, 4a, 4b by means of screws, which are either fixed,according to Figs. 1-3, in the crank case in the form of stud-bolts 3,or which are provided, according to Fig. 4, in the form of bolts I3which intersect the case in the direction at right angles to the crankshaft and by means of nuts hold each cylinder or cylinder series inposition on the crankcase.

0n the inside of the bottom 4 of the U-cavity 40 formed by the casesection the crank bearings are arranged, and are divided on a. plane atright angles to the cylinder axes. 'Ihe pedestal bodies 'I are formedintegral with the sides and bottom of the crankcase structure and bracedby walls -or` ribs 8, while the bearing caps I0 are inserted in the casefrom the open side thereof and are fastened to the pedestal bodies T bymeans of the screws indicated at 9. In order to close, on one hand, thecavity of the U-structure, and to faclli- 5. tate, on the other hand,insertion and removal of the crankshaft, the front faces of the case areformed with removable covefs or end plates I I, l2. This design of thecrankcase and crank bearings allows an easy insertion and removal of thecrank- 5,,

shaft after removal of the cylinder or cylinder series I mounted on thelegs and the simultaneous removal of the covers II, I2. This design of acrankcase further offers the advantage that the lowest'bearing pressuresoccur in the plane of the bearing joints. The upper portion of thecrankca'se-comprlsing the leg la may be formed, between the bearings,with perforations I4, which are preferably closed by a light cover I5.The lower part oi' the crankcase comprising the legs 4b is formed withan outer wall I8 extending over thelength ofthe case and is preferablytroughshaped as indicated 'in Figs. 1, 2 and 4. This portion may formthe oil sump.

Numerous advantages are connected with the novel crankcase according tothe present' invention. It complies with all requirements as to strengthto which a crankcase chiefly used in connection with vehicles issubjected. The crankcase is assembled in a self-contained unit, whichdisplays all the. advantageous characteristics of a unitary structure,such as a saving of space and y Various changes may be made in thedetails disclosed in the foregoing specification without departing fromthe invention or sacrificing the adf vantages thereof.

I claimt- '1. An internal combustion engine in which the cylinders arearranged on opposite sides of the crankshaft, comprising in combination,a crank- 'case forming a unitary structure having, at right angles tothe crankshaft, the cross-section of an U, the legs of which extendparallel to the plane passing through the cylinder axes, a series ofcylinders mounted on the bottom of said U -shaped structure and a seriesof cylinders mounted on the free ends of the legs of the crankcase so asto brace the legs relative to each other, crank bear'- ings arranged onthe inner side of said bottom and formed with a. joint extending atright anglestothe mean cylinder plane and a bearing cap for each crankbearing separately mounted in the cavityyof said U-shaped structure.

2. An internal combustion engine in which the cylinders are arranged onopposite sides of the crankshaft, comprising in combination, acrankangles to the crankshaft, the cross-section of an U, the legs ofwhich extend parallel to the plane passing through the cylinder axes, acylinder vcase forming a unitary structure having, at right v mounted onth bottom 'of said U-shaped struc- ,cylinders are arranged I.on oppositesides of the crankshaft, comprising ifn combination, a crankc'aseforming a unitary structure having, at right angles to the crankshaft,the cross-section of an U, the legs of which extend parallel to the'plane passing through the cylinder axes, a cylinder mounted on thebottom ofvsaid U-shaped strucp ture and a cylinder mounted on the freeends'ot the legs of the crankcase so as to Abrace the legs relative toeach other and removable covers bridging the gap between the legs oneither side of the' 'U-shaped structure.

KARL WImKEN.

